This invention relates to a liquid crystal display device incorporating therein an illumination lamp.
A liquid crystal display device is suitable for use as a display device of a wrist watch because it is easy to make and can be made very thin, and the power consumption is comparatively low. However, since liquid crystal material does not itself emit light, the display can not be seen very well at a dark place. The display can be read out by reflecting light provided by an outside light source.
In order to read out the display at a dark place, particularly at night, a light source must be incorporated into the display device.
There are two types of illumination means for illuminating the liquid crystal material, the light transmission type and light reflecting type. In the display device of the former, the light source is located at the back thereof so that light is transmitted directly through the liquid crystal material, on the other hand, in the display device of the light reflecting type, the light source is located at the front thereof and reflected back into the liquid crystal material. However, the construction of these display devices has the defect of increasing the overall thickness of the device thereby making them less suitable for use in small wrist watches.